Radio - Poor or No Reception (AM)
Bulletin Number:99-11
Group:
91
Date:
Dec. 9, 1999
Subject:
AM Radio, Poor or No Reception
Model(s):
1999-2000 New Golf, New Jetta, New Beetle, Passat
Supersedes T.B. Group 91 Number 99-07 dated Aug. 2, 1999
CONDITION:
AM reception is poor.
May be caused by:
^ Poor ground at the antenna base or radio
^ Poor battery ground to chassis or engine
^ Poor antenna cable connection at Radio
^ Corrosion at the antenna coaxial connectors at radio or antenna
^ An incorrect antenna mast installed for the antenna base equipped with the vehicle
SERVICE:
Checking antenna connections, electrically through radio
- Switch radio ON.
- Press and hold balance button for approx. ten seconds.
^ 3CPT7 will appear in display (numbers may vary and are not important)
- Press CD mode button.
^ 020.I will appear in display (software version numbers may vary)
- Press CD mode button again.
^ FERN OFF/ON will appear in display
Note:
FERN = amplified antenna.
If FERN ON appears:
Antenna and connections are OK.
If FERN OFF appears:
Radio may not be coded correctly for amplified antenna.
- Check for proper coding of radio, see coding table in Technical Bulletin Group 91 Number 99-09 dated Oct. 25, 1999.
^ When radio is coded according to this table, FERN is operational.
If radio is coded correctly and FERN OFF appears, then antenna and connections are not OK.
- Check antenna and connections page 3
Radio antenna, matching base to mast
Vehicles are equipped with either a Bosch or a Clarion antenna base mounted on the roof and (for shipping purposes) the appropriate matching mast is located in the luggage compartment.
If radio antenna masts are removed from vehicles and stored until vehicles are sold, there is a chance that an incorrect mast can be installed at the time of delivery.
Note:
Mismatched antenna mast and base will cause poor AM radio reception.
The antenna base and mast can be identified visually as follows:
Bosch antenna
^ Base (although oval) is more circular in shape (approx. 57 mm x 49 mm).
^ Made in Germany stamped on underside of base.
^ Two screws on underside of base are unpainted.
^ Requires gloss finish antenna mast.
Clarion antenna
^ Base is more oval in shape than Bosch (approx. 61 mm x 41 mm).
^ Two screws on underside of base are painted.
^ Requires matte finish antenna mast.
If antenna mast matches the antenna base correctly:
- Check antenna and connections
Antenna cable and connections, checking
- Check antenna coaxial cable connections -arrows- for corrosion and clean if necessary (DO NOT apply stabilant). Passat coaxial cable connection for radio is under the carpet on right side of tunnel near shifter.
Note:
DO NOT Check the antenna system by using an ohmmeter from the antenna lead to the threads where the mast -1- attaches to the base of the antenna. This will not work because the antenna system uses an amplified signal.
- Ensure that coaxial cable is firmly seated in radio (Passat cable connection, see previous step).
- Check ground at the antenna below roof Nut -4- (torque = 7+1 Nm) must firmly secure antenna to roof).
- Check ground for radio behind radio on cross member (On Passat models as of Nov. 1998 beginning VIN: XE285000 ground for radio is on right side of center tunnel).
- Check engine compartment ground, left side, below battery tray; from battery GND to body.
- Check engine/transmission ground on transmission, near engine block.
- If all grounds and antenna mast are OK.
- Replace antenna and coaxial cable assembly.